At some point growing up, my vision changed and I gradually stopped being able to see past about 10 inches in front of my face. I eventually got glasses and with them, my world turned from blurry to clear. This experience, as inconvenient as it is, is more widespread than ever before. Rates of myopia or near-sightedness, or needing glasses to see things far away, have been rising for decades. In the US, 25% of people were myopic in 1971, while by 2004 that number had risen to 42%. It is estimated that by 2050, half of the world’s population will be myopic. In Hong Kong, Singapore, Taiwan and South Korea, rates are already much higher than that.
Researchers initially thought that whether or not you needed glasses was just a matter of genetics. While it partly is, having one myopic parent doubles the odds of being nearsighted and having two increases the odds fivefold. The abruptness of this increase suggests that this change is environmental. The most likely explanation is the combination of too little daylight and too much time doing things up close. This causes the eye to strain to focus on things up close, and in response, it grows longer than it should. Exposure to bright outdoor light stimulates the production of dopamine in the retina, which regulates the eye’s growth. Without enough dopamine, the eye doesn’t know when to stop growing and indoors it’s hard to get enough. In East and Southeast Asia, children are spending less time outside, which may be due to the increased competitiveness of the education system. This lack of outdoor time can lead to serious consequences, such as myopic macular degeneration, retinal detachment, glaucoma and cataracts. To prevent these conditions, it is important to intervene as early as possible. Treatment options include multifocal soft contacts, glasses, orthokeratology or ortho-k lenses, and low doses of atropine eye drops. The most effective way to prevent myopia, however, is to get children to spend more time outside. Taiwan and Singapore have implemented successful programs encouraging students to spend two hours outside every day, and these programs have reversed the 40-year-long increase in myopia rates. To ensure the future of myopia does not look like this, we must take action now.